The basis of the invention is an observation that power losses between the belt and the pulleys are mainly caused by lateral clearances and resiliences of the sheaves and belt dominating in relation to the bearing losses. For this reason the V-belt variators have generally a clearly lower efficiency rate than non-variable transmissions.
The basic idea of the invention is to modify the bearings of the sheaves by such a way, that the sheaves are not parallel when they are non-loaded or the belt is missing between them, but so inclined to each other that bending load caused by the belt makes them approximately parallel.
In itself it is not a new idea to make the sheave halves of a variable pulley non-parallel. It is known for example in the patent publications U.S. Pat. No. 3757594 (F 16 H 55/52) and G. 2041116 A (F 16 H 9/12).